Compounded mineral oil



Patented Jan. 14, 1941 COMPOUNDED MINERAL 01!.

Bruce B. Farrington and James 0. Clayton, Berkeley, Calii., assignors to Standard Oil Company of California, San Francisco, Calif.I a corporation of Delaware N 0 Drawing.

27 Claims.

This invention relates to a new and useful composition of matter and involves a composition comprising a hydrocarbon oil and an alkaline earth salt of certainsubstituted acids of phosphorus.

The production of improved hydrocarbon oils and particularly of lubricating oils having desired characteristics has been the subject of extensive research and investigation in recent years. Generally speaking, the compounding of hydrocarbon oils to obtain desired characteristics involves empirical phenomena and the action of untested types of compounding agents cannot be predicted.

'A characteristic which has been the subject'of extensive investigation is the tendency of hydrocarbon oils to deteriorate or partially decompose and oxidize when subjected to high temperatures. This deterioration is evidenced by the deposition of adhesive deposits on hot metal surfaces over which the hydrocarbon oil may flow. It is important that resistance to such deterioration be imparted to hydrocarbon oils, particularly to lubricating oils, in order that such compositions may be relatively free from the tendency to form such deposits even under high temperatures and severe operating conditions. A direct result of this type of deterioration during lubrication of internal combustion engines, such as engines of zone temperatures of from approximately 425 to 650 F. and pressures from the oxidizing combustion gases as high as 750 to 1150 lbs. per sq. in. Addition agents which render hydrocarbon oils resistant to deterioration by heat at high temperature levels in the order of those above menpart increased stability to hydrocarbon oils, or

which are effective at temperatures even as high as 200 or 250 F. are often ineffective under the more severe operating conditions and higher temperature levels to which lubricating oils are subjected in Diesel engines. Thus the operativeness of a stabilizer at atmospheric tempera- Application November 21, 1938, Serial No. 241,647

(Cl. 252-39) I tures, or even temperatures as high as 200 to 300 F., gives no adequate basis for predicting the action of the same stabilizing agent at materially higher temperatures and under more severe operating conditions. T- disclosures in the prior art relative to such s abilizers therefore cannot serve as a guide for one seeking stabilizing agents or oxidation inhibitors effective at higher temperature levels. The phenomena involved are catalytic in nature, highly l0 empirical, and require extensive experimentation to determine the action of a given type of addition agent.

The present invention involves the discovery that dispersion of alkaline earth metal salts of i6 substituted oxy-acids of phosphorus in hydrocarbon oils, such as mineral lubricating oil, imparts new, unpredictable, and highly desirable properties to the composition. These new properties render the compounded oil particularly useful for various purposes. For example, oil soluble alkaline earth organo-phosphates like calcium cetyl phosphate, calcium lauryl phosphate, calcium cetyl-phenyl phosphate, and calcium octadecyl phosphate are capable of imparting'to crankcase lubricants in internal combustion engines increased color stability, resistance to sludging, and low wear rates while simultaneously inhibiting corrosion of modern bearing metals such asicopper-lead and cadmium-silver alloys.

In general it has been discovered that the new mineral oil compositions herein disclosed are more stable to heat and more resistant to oxidation than is'the hydrocarbon oil with which the compositions are compounded. The new compositions of this invention are therefore useful where resistance to deterioration by heat or oxidation is important. An example of suchutility other "than use as a lubricating oil comprises use as a heat transfer fluid whereit may be desirable to inhibit or prevent the formation of deposits on the metal surface from or to which heat is being conveyed. The increased resistance to oxidation imparted to the oil by the compounds of this invention will find various applications as, for instance, in an insulating, switch, or transformer oil.

It .has also been discovered that calcium salts of substituted phosphoric acids in particular.

to decrease the wear rate on cylinder walls and piston rings as compared with uncompounded minerals oils; not only freedom from corrosive action on bearing metals such as cadmiumsilver and copper-lead alloys, but the capacity to actually inhibit corrosion of such materials. Although various compounded mineral oils are known which are capable of inhibiting piston ring sticking, the discovery of specific compounding agents capable oi imparting the above combination 01 properties to hydrocarbon oils represent an unobvious and important contribution.

Alkaline earth metal salts oi substituted oxyacids of phosphorus which may be added to bydrocarbon oils to provide a new composition of matter of the type herein involved comprises salts of metals selected from Group II of Mendeleeil's Periodic Table of the Elements. Specific examples of such metals are calcium, strontium, and barium. The term alkaline earth metals" as used herein is intended to designate generically the left hand sub-group of Group II o! the Periodic Table.

The metal salts of this invention are Preferably formed from substituted oxy-acids of .pentavalent phorus of the following type formulae:

where R and R may be alkyl, aryl, alkaryl, aralkyl or cyclic non-benzenoid radicals. Preferably substituted phosphoric acids containing at least twelve carbon atoms are utilized. Examples of preferred type acids are alkyl or alkaryl substituted phosphoric acids having at least twelve carbon atoms in the molecule. However, it is to be understood that the broader aspects oi the invention include other substituted oxy-acids of phosphorus which contain more than twelve carbon atoms. Additional examples of oxy-acids of phosphorus which may be used in forming the metal salts of the present invention are as follows:

P) OH phosphonic acid;

mono-esteroi phosphonic acid;

POH R ii phosphinic acid. In all of the above formulae R. and R may be alkyl, aryl, alkaryl, aralkyl or cyclic non-benzenoid groups. 7

Alkaline earth metal salts of substituted derivatives of acids of phosphorus such as phosphorous acid, HaPOa; hypophosphorlc acid,HzP0:; onthophosphoric acid, HaPOi; and pyrophosphoric acid, H4P2O7, are regarded as falling within the broadest aspects of. the invention.

By substituted or substituted derivatives of" acids of phosphorus whenever used herein, it is intended to designate acids containing an organic group of the type previously listed, 1. e., alkyl,

aaaaeee aryl, alkaryl, aralkyl, or cyclic non-benzenoid groups. The organic groups may be either directly attached to the phosphorus atom of the compound or attached thereto through an intervening atom such as oxygen. The term "oxyacids of phosphorus" is intended to designate throughout the specification and claims acids of phosphorus in which one oxygen atom may intervene between the hydrogen and phosphorus atoms of the ester.

The preferred acids are substituted onthophosphoric acids and the preferred salts comprise the calcium salts of these acids. Examples of such salts are calcium lauryl phosphate, calcium cetyl phosphate, calcium octadecyl phosphate, calcium "spermol phosphate, calcium oleyl phosphate, calcium "spermenyP phosphate, calcium" cetyl phenyl phosphate, and calcium di-(amylphenyl) phosphate. Additional examples or salts within the scope of the invention are: calcium di-stearoglyceryl phosphate, calcium naphthenyl phoswhere R is an alkyl radical. The alkyl ethyl phosphoric acid is soluble in ether, while the ethyl meta phosphate is not and the ether solution of the former may be separated from the latter by decantation. Table I gives a number of examples of substituted phosphoric acids suitable ior the purposes of this invention and a brief indication as to their method of preparation.

Table I 9.25 lb. cetyl alcohol and 5.61 lb. P10 refluxed with 5 gal. ethyl other for 24 hr. cetyl-phoephoric acid solution decanted.

rm alcohols, 60 400 gms. ether Monccetylphosphoric 112 gms. solid s gms. P10; an treated as above.

gms. octadecyl alcohol and c.c. benzene treated with 56.8 firrns. POCh. Product was byolyled.

Mono-spermol" phosphoric..-

Mono-octadecylphospherio.

107 gms. oleyl alcohol (crude octedeoenol) and 28.5 gms. P 0; were refluxed in ethyl ether for 24 hr.

107 gms. liqfuid sperm alcohols and 27 ms. ,0; refluxed in ethyl Mono-oleylphosphoric M ono-spermenyw phosphorether for 24 hr.

Dic clohexnnylph horic 150 gms. cyclohennol and 87 gms. y 05p P10; refluxed with 150 gms. ethyl ether for 24 hr.

(Cetylphenyl) phosphoric 688 gms. cetyl hcnol and 316 gms.

P10 reflux with ethyl ether in: 24 hr.

100 gms. amyl phenol and 43 gms.

PgO heated to F. for 15 hr.

Di (emylphenyl) phosphoric...

In preparing the alkaline earth metal salts herein involved, the ethyl group in the ethyl phosphoric acid above mentioned may be hydrolyzed 01! to form the metal salt of the monoalkyl-ortho-phcsphoric acid, 1. e., the salt 0! RHaPOe. This type of operation isnot limited to the alkyl derivatives, but includes aryl-ethylphosphoric acid, alkaryl-ethyl-phosphoric acid,

aralkyl-ethyl-phosphoric acid, and ethyl phosphoric acids containing a cyclic non-benzenoid p.

The alkaline earth metal salts of the various substituted oxy-acids of phosphorus may be conveniently prepared by reacting the acid with sodium hydroxide or potassium hydroxide and then precipitating the desired metal salt from the solution of the sodium or potassium salt by the adder liners of engines, and was easily precipitated from solution in the oil in the presence of water. The same is true of 1% sodium cetyl phosphate in oil.

In the above piston ring sticking tests a single- 5 cylinder2% inch bore, 2 /2 inch stroke Lauson gasoline engine was operated under extremely severe condition-s'for the purpose of developing fully pistonring sticking and piston gumrning-- drocarbon oils. Corresponding alkali metal salts are not equivalent to the alkaline earth salts by reason of the fact that the potassium salts, for example, 1% potassium cetyl phosphate in oil has 75 caused scratching of the pistons, rings and cylindition of the appropriate metal ion. The salt tendencies under circumstances simulating severe 10 may also be prepared by the direct neutralizaoperating conditions encountered in the field. tion of the acid, as, for example, with line where Operation of the motor during tests was continuthe calcium salt is to be obtained. ous at 1600 R. P. M. except for periodic. shut-' Where the metal salt is prepared by precipidowns at -hour intervals for inspection. The

15 tation from asolu-tion of the sodium or potassium jacket temperature was maintained at 375 F. 15 salts of substituted orthophosphoric acids, it has and the sump oil temperature at 220 F. been observed that the sodium or potassium salts The wear tests were carried out in a Weeks are co-precipitated to some extent with the demachine comprising a inch steel ball pressed sired alkaline earth metal salt. It is preferred against at 1% inch steel cylinder with a force to maintain the amount of co-precipitated alkali of 40 lbs., the cylinder dipping in the oil to be 20 metal salt in the alkaline earth metal compound tested and rotating at 600 R. P. M. The duration at a minimum because the alkali metal salt deof the test was 16 hours and the wear rate decreases the stability of the oil solution in the termined by measuring the amount of metal. re-

presence of water. moved from the ball. In the above weartests the The alkaline earth salts herein disclosedmay lubricant was maintained at approximately 300 be prepared in a non-aqueous environment by the F. as indicated. reaction of the alkaline earth metal carbide, e. g., The corrosion tests were carried out in'the folcalcium carbide with the free substituted acids lowing manner: Glass tubes 2 inches in diameter of phosphorus. and 20 inches long were immersed in an oil bath,

By way of illustration and to demonstrate the the temperature of which was automatically con- 0 unique properties possessed by the compounded trolled to within *-1 F. of the test temperature, oils of this invention, the data in Table II are which was 300 F. Approximately 300 c. c. of oil given: under the test was placed in each tube and air a 5 Table II Engine tests, Lauson Miscellaneous data Strip corrosion 40 compound the as mitts. o

Cu-Pb Oil- Ag Vis. 3%.

increase (1) (2) 10; F. (or

None 0 Calcium lauryl phosphate. l. 0 calc igign cetyl phosphate 833$ ??Ipi 3ilf .3??f?::: 313 Barium oetyl phosphate l. 0 Calcium (cetyl phenyl) phosphate... 0.5

acidglgfllgairgfieei. alga. tune to stick rings of coumpounded oil to that-with an uncompounded Western (2 Expressed as ratio of compounded "oil corrosion to corrosion with Western acid refined oil, S. A. E. 30. (3 Expressed asratio of wear of compounded oil to that oi Western acid refined oil, 8. A. E. 30. Indicates corrosion measured in Lauson engine during ring-sticking tests.

The above data show that compounds of the was bubbled through it at the rate of'10 liters type herein disclosed impart to lubricating oils per hour. Strips of the different types of bearincreased re ista deterioration y at 0 mg metals were'cut to size and placed in the oils; oxidation, inhibit piston ring sticking in internal in most cases the copper-lead and cadmium-silcombustion engines, increase the cleanliness of ver bearing alloys were tested simultaneously in engine pistons, are essentially non-corrosive, the same sample of oil. The weight loss of each 1 actually inhibit corrosion of copper-lead and cadstrip was recorded. Before weighing, eachstrip mium-silver bearings Strip Corrosion tests, and was washed in petroleum ether and carefully reduce wear of metallic frictional surfaces. It wiped with a soft cotton cloth. The duration of has also been discovered that the alkaline earth the test was '12 hours. 05 metal salts of substituted oxy-acids of phos- The compounding agents herein disclosed may phorus form stable solutions in oil which are not have one or more advantages depending upon the' easily precipitated. Tests show that the comparticular compound selected, the proportion utipounds herein disclosed are excellent oxidation lized, .andthe environment which the lubricating inhibitors and color stabilizers for mineral hy oil is to encounter. It should be observed, for

example, that eventhough a compounded oil may be somewhat corrosive to copper-lead or cadmium-silver bearing metals, Babbitt bearings are little if at all afl'ected by such corrosive action. Hence, a compounded oil which may not be particularly desirable for lubrication of copperlead or cadmium-silver bearings may be highly useful and extremely advantageous in conjunction with the operation of internal combustion engines having bearings of Babbitt or other corrosive-resistan-t bearing metals. The present in-- properties desired-involve the ability to stabilizelubricating oils under severe operating conditions such as those encountered in the lubrication of pistons and piston rings of internal combustion engines of the Diesel type, alkaline earth metal salts of substituted oxy-acids of pentavalent phosphorus containing more than twelve carbon atoms in the molecule and preferably containing an alkyl or alkaryl substituent should be utilized if the most efilcient results are to be obtained.

A moderately acid refined Western naphthenic base oil is the preferred oil stock used as a base for the compounded lubricants involved herein. The compounding ingredients appear to function more efiiciently in such a base oil than in a highly paraiiinic oil stock or a highly refined Western oil. However, it is to be understood that the invention is not limited to any particular base stock since advantages herein disclosed may be obtained at least to some degree with various oil stocks, the selection of which will be determined by conditions and service which the compounded lubricant is to encounter.

The proportion of alkaline earth metal salts of substituted oxy-acids of phosphorus added to mineral oils may vary widely, depending on the sistance to extremely high temperatures, such as encountered in Diesel engines, and ability to inhibit piston ring sticking comprise the principal properties desired. Solutions containing more than 2% of the compound in mineral oil may be utilized for the purpose of preparing lubricating greases and concentrates capable of dilution with lubricating oils and the like. Such higher concentrations comprise a convenient method of handling the compounds and the concentrated solutions may be used as addition agents for lubricants in general, as well as for other purposes.

The metal salts of this invention may be added to hydrocarbon oils containing other compounding ingredients such as pour point depressors, oiliness agents, extreme pressure addition agents, blooming agents, compound for enhancing the viscosity index of the hydrocarbon oil, corrosion inhibitors, color stabilizers, etc. The invention in its broader aspects embraces mineral hydrocarbon oils containing, in addition to metal salts of substituted acids of phosphorus, thickening agents and/or metal soaps in greaseforming proportions or in amounts insufficient to form greases, as in the case of mineral castor marihine oils or other compounded liquid lubrican s.

While the character of the invention has been described in detail and numerous examples of the composition given, this has been done by way of illustration only and with the intention that no limitation should be imposed on the invention thereby. It will be apparent to those skilled in the art that numerous modifications and variations of the illustrative examples may be effectedin the practice of the invention which is of the scope of the claims appended hereto.-

We claim:

1. A composition of matter comprising a hydrocarbon oil and a strontium salt of a substituted oxy-acid of phosphorus containing an organic substituent.

2. A composition of matter comprising a viscous hydrocarbon oil and a strontium salt of an acid of the type formula:

wherein R is a hydrocarbon radical.

3. A composition of matter comprising a viscous hydrocarbon oil and an alkaline earth metal salt of an acid of the type formula:

wherein R and R are hydrocarbon radicals.

4. A composition of matter comprising a viscous hydrocarbon oil and a calcium salt of an acid of the type formula:

wherein R and R are hydrocarbon radicals.

5. A composition of matter comprising a viscous hydrocarbon oil and a barium salt of an acid of the type formula:

wherein R and R are hydrocarbon radicals.

6. A composition of matter comprising a viscous hydrocarbon oil and a strontium salt of an acid of the type formula:-

wherein R and R are hydrocarbon radicals.

'7 A composition of matter comprising a lubricating oil and a strontium salt of an alkyl substituted phosphoric acid containing more than twlelve carbon atoms.

8. A composition of matter comprising a lubricating oil and an alkaline earth metal salt of an alkaryl substituted phosphoric acid containing more than twelve carbon atoms.

9. A composition of matter comprising a lubricating oil and a calcium salt of an alkaryl substituted phosphoric acid containing more than twelve carbon atoms.

10. A composition of matter comprising a lubricating oil and a barium salt of an alkaryl substituted phosphoric acid containing more than twelve carbon atoms.

11. A composition of matter comprising a lubricating oil and a strontium salt of a .alkaryl substituted phorphoric acid containing more than twelve carbon atoms.

12. A composition of matter comprising a hydrocarbon lubricating oil subject to deterioration at elevated temperatures, and a minor proportion based on said oil of an alkaline earth metal salt of a substituted acid of phosphorus containing an organic substituent, said salt being present in an amount sufiicient substantially to inhibit said deterioration.

13. A composition of matter comprising a hydrocarbon lubricating oil subject to deterioration at elevated temperatures, and from approximately 0.05% to approximately 2% by weight based on said oil of an alkaline earth metal salt of a substituted acid of phosphorus containing an organic substituent, said salt being of a type capable of inhibiting deterioration of said lubricating oil.

14. A composition of matter comprising a hydrocarbon lubricating oil subject to deterioration at elevated temperatures, and a minor proportion based on said oil of a calcium salt of a substituted acid of phosphorus containing an organic substituent, said salt being present in an amount sufficient substantially to inhibit said deterioration.

15. A composition of matter comprising a hydrocarbon lubricating oil subject to deterioration at elevated temperatures, and a minor proportion based on said oil of a barium salt of a substituted acid of phosphorus containing an organic substituent, said salt being present in an amount sumcient substantially to inhibit said deterioration.

16. A composition of matter comprising a hydrocarbon lubricating oil subject to deterioration at elevated temperatures, and from approximately 0.05% to approximately 2% by weight based on said oil of an alkaline earth metal salt of a substituted pentavalent oxy-acid of phosphorus containing an organic substituent, said salt being of a type capable of inhibiting deterioration of said lubricating oil.

1'7. A composition of matter comprising a hydrocarbon lubricating oil subject to deterioration at elevated temperatures, and from approximately 0.05% to approximately 2% by weight based on said oil of a calcium salt 0! a substituted pentavalent oxy-acid of phosphorus containing an organic substituent, said salt being of a type capable of inhibiting deterioration of said lubricating oil.

18. A composition of matter comprising a hydrocarbon oil and an alkaline earth metal salt of an alkyl substituted acid of pentavalent phosphorus containing more than twelve carbon atoms in the molecule.

19. A composition of matter comprising a hydrocarbon oil and a calcium salt of an alkyl substituted acid of pentavalent phosphorus containing more than twelve carbons atoms in the'molecule.

20. A composition of matter comprising a hydrocarbon oil and a barium salt of an alkyl substituted acid of pentavalent phosphorus containing more than twelve carbon atoms in the molecule.

21. A composition of matter comprising a hydrocarbon oil and an alkaline earth metal salt of a dibasic oxy-acid of pentavalent phosphorus containing a substituent of hydrocarbon structure.

22. A composition of matter comprising a hydrocarbon oil and a calcium salt of a dibasic oxy-acid of pentavalent phosphorus containing a substituent of hydrocarbon structure.

23. A composition of matter comprising a hydrocarbon lubricating oil and from approximately 0.05% to approximately 2% by weight based on said oil of an alkaline earth metal salt of a substituted acid of pentavalent phosphorus containing an alkyl substituent of more than twelve carbon atoms.

24. A composition of matter comprising a hydrocarbon Lubricating oil and from approximately 0.05% to approximately 2% by weight based on said oil of a calcium salt of a substituted acid of pentavalent phosphorus containing an alkyl substituent of more than twelve carbon atoms.

25. A composition of matter comprisinga hydrocarbon lubricating oil and from approximately 0.05% to approximately 2% by weight based on said oil of calcium cetyl phosphate.

26. A composition of matter comprising a hydrocarbon lubricating oil containing more than 0.05% by weight based on the oil of an alkaline earth metal salt of a substituted acid of phosphorus containing an organic substituent.

27. An addition agent, capable of inhibiting piston ring sticking, for lubricating oils, comprising a concentrated solution in mineral oil of an alkaline earth metal salt of a substituted acid of phosphorus containing an organic substituent, said solution being capable of dilution with mineral lubricating oil to form a homogeneous mixture containing from approximately 0.05% to 2% by weight of the alkaline earth metal salt based on the total amount of lubricating oil.

. BRUCE B. FARRINGTON.

JAMES O. CLAYTON. 

